Tuyere shield



April 8, 1942. T. H. KENNEDY TUYERE SHIELD Filed July 25, 1941 2Sheets-Sheet l [mm liar." 7 UMfl/V H KEN/V50),

April 28, 1942.

T'. H. KENNEDY TuYEaE SHIELD Filed July 25, 1941 2 SheetsSheet 2Patented Apr. 28, 1942 l I UNITE TUYERE SHIELD Truman H. Kennedy,McKeesport, Pa., assignor to National Tube Company, a corporation of NewJersey 6 Claims.

The present invention relates to an improved tuyere shield for theprotection of workmen in the vicinity of the penstock, blow pipe andtuyres of a blast furnace.

As is well known to those skilled in the art, in the normal operation ofa, .blast furnace used for the smelting of iron, admixtures of fuel cokeand a limestone fiux are combusted by the introduction of hugequantities of preheated air forced into the furnace under pressure. Thisair is heated in conventional blast furnace stoves and is fed through abustle pipe surrounding the furnace. From the bustle pipe branches,known as penstocks, air is led through blow pipes directly into thefurnace through hollow sleevelike elements known as tuyeres.Conventional tuyres are detachably mounted in tuyere coolers embedded inthe walls of the furnace and the inner extremities of the tuyere projectbeyond the inner wall of the furnace.

To prevent the untimely burning out of the tuyere or the untimelymelting thereof under the intense heat of the furnace, provision isusually made for the continuous circulation of cooling,

water through both the tuyere and the tuyere cooler. Generally an eyepiece or peep sight is mounted in the lower portion of the penstock topermit the furnace operator to observe the condition of the molten metalin the crucible of the furnace.

In normal operation, during the operation of the furnace the burdentherein slowly moves downwardly in a more or less continuous orintermittent manner. The gravitational movement, coupled with otherinternal activities within the furnace, gradually erode the interiorwall surfaces of the furnace. The tuyeres projecting beyond the innersurface of the furnace Walls are therefore normally exposed to thescouring action of the downwardly moving burden, and are also exposed tothe destructive action of the ebullient molten metal. When thecirculation of cooling water fails to properly function, or when thewalls of the tuyere become fractured or worn thin by abrasion, or whenthey are unable to longer resist the internal forces within the furnacedirected against them, they occasionally burn out and become eitherwholly or partially destroyed.

Such accidental occurrence, while infrequent, nevertheless does happenat intervals during the normal life of a furnace. Upon the failure of atuyere, cooling water frequently escapes into the furnace and thecontents of the furnace have a tendency to rush to the accidental exitpoint thus provided, the molten metal thus tending to rapidly flow fromthe furnace with a violent or volcanic eruptive force. Upon suchoccurrence, the hazards are three-fold; the escape of heavy hot fluidmasses, the escape of hot gases, and the escape of steam generated bythe tuyre cooling water contacting the hot metal flowing from thefurnace.

The present invention aims to provide an improved means for protectingthe workmen at the time of tuyere failure by the provision of animproved shield so designed and arranged that it will not interfere withthe normal furnace operation or interfere with the view of the furnaceoperator, and also so arranged that the protective device can be readilyattached and coordinated with conventional types of blast furnaceequipment. From an economic standpoint it is important that anyprotective device be of simple design and rugged construction and thatit be adaptable to conventional types of furnace equipment, since thecapital investment for a blast furnace runs into very high figures. Thepresent invention is believed to meet these practical and economicrequirements because of its simplicity of construction and itsadaptability to attachment to standard equipment.

The invention will be fully apparent from the following detaileddisclosure when read in connection with the accompanying drawings, andwill be defined with particularity in accordance with the requirementsof the patent statutes in the subjoined claims.

In the drawings: 7

Figure 1 is a fragmentary view showing the lower portion of aconventional type of blast furnace equipped with the improved shield ofthe present invention;

Figure 2 is an enlarged detail view showing a portion of the penstock,blow pipe and improved tuyre shield;

Figure 3 is a detail view of the improved shield detached from thefurnace, the view being taken on line III-III of Figure 2;

Figure 4 is a fragmentary detail of one of the component parts of theimproved shield illustrating the specific construction and mounting ofpintle pins and related parts in the vicinity thereof to facilitateassembly and detachment of the parts;

Figure 5 is a detail section on line V--V of Figure 3 illustrating meansfor detachably looking the shield plates to one another; and

Figures 6 and '7 are detail sections on the correspondingly numberedlines of Figure 3.

Referring in detail to the drawings, the numeral It] represents theportion of a blast furnace within which there is mounted a plurality ofconventional water cooled tuyere coolers i2. Each tuyere cooler hasdetachably mounted therein a tuyere [4 which is also of hollowconstruction and water cooled in a conventional manner. inner nose [6 ofthe tuyere projects beyond the inner surface l8 of the hearth orcrucible wall in accordance with standard practice. Because of thisnecessary inward projection of the tuyere it occasionally happens thatthe same burns away and causes the undesired expulsion of hot metal andgas as hereinabove referred to.

Surrounding the furnace there is the usual bustle pipe 29 through whichthe blast air is supplied. At regular intervals around the furnace thereare branches in the form of conventional penstock fittings 22.Connecting each penstoc with each tuyere there is normally provided ablow pipe 24 and there is a detachable joint sleeve-like structure 25 tofacilitate breaking the connection between the blow pipe, tuyere and 1penstock. The lower end of the penstock is yieldingly pressed intoengagement by means of a spring 28 surrounding a rod 38 which has apivotal connection with a fixed jaw 32 secured to the furnace structure.stock, blow pipe tuyere and tuyere cooler are all of standardconventional form well known to those skilled in the art and no claim ismade to the structure thereof apart from its combination with theprotective shield to now be referred to.

However, it is to be understood that the shield of the present inventionis purposely so designed and arranged that it can be readily mounted foruse in combination with the conventional forms of blast furnaceequipment operated in connection with many steel plants throughout thecountry.

The improved tuyere shield of the present in-. vention consistsessentially of two oppositely disposed substantially semicircular plates34 and 33 whose interior portions are provided with semicircular notches38 and 49 which make a neat fit around the joint element 25 in theregion where the penstock 22 connects with the blow pipe 24. Secured atdiametrically opposite points on the penstock, by means of bolts 42 and44, there are respective hinge elements 46 and 48 having respectivepairs of hubs 59 and 52 each formed with substantially vertical openingstherein adapted to receive the respective pairs of hinge pintles 54 and58 which depend from hinge lugs 58 and 69 welded or otherwise secured tothe shield plates 34 and 35. To facilitate assembly and disassembly ofthe hinge plates 34 and 36, the latter are notched as indicated at 82and 64 in the region of the lower pintle pins.

As thus notched, the plates can be lifted vertically so as to free thepintle pins after each half plate has been rotated 90 and brought into aposition substantially parallel to the axis of the tuyere or blow pipe.

To facilitate the turning of the plates on the hinge, a plurality ofbars or handles 66 and 68 are provided as shown.

Each plate 35 has welded thereto a striker strip 10 which is arrangedfor overlapping relationship with the inner vertical edge of thecoacting plate 34. Means are provided for detachably locking the shieldplates to one another. This means may conveniently take the form ofaper- The The bustle pipe, peniii) tured lugs 12 secured to the strikerstrip '10, the lugs being arranged to pass through slots 14 formed inthe plate 34. Keepers or looking pins 76 are adapted to pass through theapertures in the lugs 12 so as to thus detachably lock the shield platesto one another. The locking pins are conveniently held captive byflexible members, such as chains E8, the extremities 80 of which arewelded or otherwise secured to the plate 34.

The structure shown and described is of simple yet rugged construction,and can be easily and quickly mounted on conventional blast furnaceequipment. When in the locking position shown, the shield will serve toadequately protect workmen operating the furnace, yet it will notinterfere with normal furnace operation nor will it interfere with theremoval of the blow pipe or tuyeres, it being understood that at thetime of tuyere changes the locking pins '16 will be removed and theplates 34 and 36 will be swung out of the way about the hinged mountingsdescribed.

It will be understood that the shield of the present invention is notexpected or intended to hold back permanently any violent effiux ofliquid or gaseous materials coming from the furnace at the time of theaccident. However, it is intended to, and in practice actually does,materially check or bafile the initial fiow of metal or gases so thatoperators working in proximity to the tuyere will have ample opportunityto escape to a point of safety before the shield itself becomesdestroyed by the onrunning molten metal or hot destructive gases. Itwill be understood by those skilled in the art that at the time of theaccident, the gases and steam emitted from ruptured tuyeres travel withgreat rapidity and these accidents usually occur without much previouswarning. However, the initially escaping gases do produce loud audiblesounds which serve to forewarn the operators of the impending danger sothat they can escape to a point of safety.

It is during this initial danger period that the tuyere shield of thepresent invention effectively serves to protect the workmen. Usually incase of accident a prearranged procedure is followed, including theshutting off of the air blast and the taking of other protectivemeasures known to those skilled in the art.

While I have described quite precisely the embodiment of the inventionherein illustrated, it is to be understood that the drawings anddescriptive matter are to be interpreted in an illustrative rather thana limiting sense.

I claim:

1. In a blast furnace, the combination with the penstock, blow pipe andtuyere thereof, of a shield comprising two coacting notched plateshingedly mounted between the penstock and the tuyere and surrounding theblow pipe.

2. In a blast furnace, the combination with the penstock, blow pipe andtuyere thereof, of a shield comprising two plates with their innerportions arcuately notched to make a neat fit around the structure wherethe blow pipe joins the penstock, the inner portions of the platesoverlapping, and respective means for pivotally supporting each of saidplates for movement about upright axes on opposite sides of thepenstock.

3. In a blast furnace, the combination with the penstock, blow pipe andtuyere thereof, of a shield comprising two coacting notched plateshmgedly mounted between the penstock and the tuyere and surrounding theblow pipe, and coacting means on said plates detachably locking them toone another.

4. In a blast furnace, the combination with the penstock, blow pipe andtuyre thereof, of respective plates hingedly mounted on upright hingessecured to diametrically opposite parts of the penstock, the innerportions of said plate being notched so as to make a neat fit with thestructure in the region where the penstock connects with the blow pipe,and coacting means on said plates detachably locking them to oneanother.

5. In a blast furnace, the combination with the penstock, blow pipe andtuyre thereof, of a shield comprising two approximately semicircularplates with approximately semicircular notches formed in the interiorthereof, respective hinge elements secured to opposite sides of thepenstock, each plate having respective pintles for engagement with saidelements, and means detachably locking the plates to one another.

6. In a blast furnace, the combination with the penstock, blow pipe andtuyere thereof, of a shield comprising two approximately semicircularplates each formed at their interior with an approximately semicircularnotch, one of said plates having striker strips secured theretooverlapping the other plate, an apertured lug mounted by one of saidstriker strips and extending through an opening formed in the plateoverlapping it, and a keeper pin engageable with the aperture in the lugfor detachably locking the coacting shield plates to one another.

TRUMAN I-I. KENNEDY.

